On Wed, 2002-08-28 at 11:38, Peter F. Patel-Schneider wrote:
[...]
> How the issues are resolved can only be completely determined by
> understanding the various documents. However, the basics are as follows:
The progress on semantic layering looks interesting...
> Issue 5.3 Semantic Layering
> The semantic layering of OWL on top of RDFS is that OWL is a theory
> in an extension of RDFS. In this theory, the OWL domain of
> discourse is not the entire RDF domain of discourse.
but the features of the language you're talking about are
very different from the features I'm interested in:
>
> Issue 4.6 EquivalentTo
> EquivalentTo is removed from the language, as it is ill-typed.
> Issue 5.1 Uniform treatment of literal/data values
> There is a strict separation between OWL object and data values.
> Removing the separation has computational consequences.
I'm not interested in a language like that.
The most important feature of the ontology layer, for me,
is daml:UnambiguousProperty, as specified by the axiomatization.
i.e. the ability to say "if X and Y have the same
state code, they're the same thing."
(for details, see these test materials:
http://www.w3.org/2002/03owlt/sameStateP.rdfhttp://www.w3.org/2002/03owlt/sameStateC.rdf
)
I've seen suggestions that WebOnt should persue the description
logic features (tractable inference etc.) but some of the
useful looking features of DAML+OIL (UnambiguousProperty,
equivalentTo) should be added to RDFS. Those properties
were in earlier drafts of RDFS, after all; they were
left out because the WG wasn't clear on how to formalize
them. But now that we've got a formal understanding
of how RDFS works, it's no problem to add them.
I was thinking of this WG as the group to add those
features back on top of RDFS, but maybe that's not
what folks want to do.
--
Dan Connolly, W3C http://www.w3.org/People/Connolly/